秋、冬季渤海溶解N2O的分布和通量及其影响因素

通过2019年10月和12月对渤海海域进行的调查及样品采集，分析溶解N₂O的分布和影响因素，并估算其海-气交换通量。结果表明：秋季表层海水溶解N₂O浓度为(8.2±0.5)nmol/L，饱和度为(97.5±4.7)%；冬季浓度为(11.0±0.8)nmol/L，饱和度为(93.8±4.5)%。渤海表层海水溶解N₂O浓度呈现明显的季节性差异，冬季浓度高于秋季，且高值区均集中在黄河口以及莱州湾附近。秋季渤海溶解N₂O处于接近饱和状态，冬季则处于不饱和状态。温度、陆源淡水输入以及沉积物-水界面交换对渤海溶解N₂O的分布有重要影响。2019年10月和12月黄河向渤海输入N₂O的量分别约为4.2×10⁴ mol和1.1×10⁴ mol，是渤海N₂O的重要来源，而秋、冬季渤海底层的沉积物既可能是渤海水体N₂O的源，也可能是其汇。秋季和冬季渤海N₂O海-气交换通...

Distributions and fluxes of dissolved nitrous oxide in the Bohai Sea in autumn and winter and their influencing factors

Distributions and air-sea fluxes of dissolved N₂O in the Bohai Sea were investigated in October and December 2019. Dissolved N₂O concentrations in surface waters were (8.2±0.5) nmol/L (97.5%±4.7)% saturation] in autumn and (11.0±0.8) nmol/L (93.8±4.5)% saturation] in winter. Generally, surface N₂O concentrations in winter were higher than in autumn. High N₂O concentrations were observed mainly near the Yellow River Estuary and Laizhou bay. N₂O in the Bohai Sea was close to saturation in autumn and undersaturated in winter. Temperature, riverine input and sediment-water exchange are major factors affecting distributions of dissolved N₂O in the Bohai Sea. The freshwater input from the Yellow River was an important source of N₂O in the Bohai Sea, with fluxes of about 4.2×104 mol in October 2019 and 1.1×104 mol in December 2019. Sediment can act as either a source or a sink of water column N₂O in autumn and winter. The air-sea fluxes of the Bohai Sea were about (?0.3±0.7) μmol/(m2?d) in autumn and (?1.1±1.6) μmol/(m2?d) in winter, and were lower than from other coastal seas of China. The Bohai Sea acted as a N₂O sink of the atmosphere in autumn and winter with a total influx of 4.41×10?4 Tg.